Antiviral indoles

ABSTRACT

Compounds of the formula (I): 
                         
wherein A, B, D, M, Ar, W, X, Y, Z and R 1  are as defined herein, are useful in the prevention and treatment of hepatitis C infections. The compounds, their preparation, pharmaceutical compositions containing them and their use in medicine are disclosed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to British Provisional application GB 0625349.6, filed Dec. 20, 2006, which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to macrocyclic indole compounds, to pharmaceutical compositions containing them, to their use in the prevention and treatment of hepatitis C infections and to methods of preparation of such compounds and compositions.

BACKGROUND OF THE INVENTION

Hepatitis C(HCV) is a cause of viral infections. There is as yet no adequate treatment for HCV infection but it is believed that inhibition of its RNA polymerase in mammals, particularly humans, would be of benefit.

Published International patent application WO 2005/080399 (Japan Tobacco Inc.) discloses the following fused heterotetracyclic compounds:

where A, X, Cy, G¹, G², G³, G⁴, G⁵, G⁶, R¹, R², R³, R⁴, R⁵, R⁶ and a are defined therein, and their use as HCV polymerase inhibitors.

Published International patent application WO 2006/020082 (Bristol-Myers Squibb Company) discloses the following fused tetracyclic compounds:

where A, B, R¹, R², R³ and n are defined therein, and their use in treating hepatitis C.

Published International applications WO 2006/046030 and WO 2006/046039 (both Istituto Di Ricerche Di Biologia Molecolare P. Angeletti SpA) disclose certain tetracyclic indole derivatives:

wherein R¹, R², A, Ar, W, X, Y, and Z are defined therein, useful for the treatment or prevention of infection by hepatitis C virus.

SUMMARY OF THE INVENTION

Thus, the present invention provides the compound of the formula (I):

wherein

Ar is a moiety containing at least one aromatic ring and possesses 5-, 6-, 9- or 10-ring atoms optionally containing 1, 2 or 3 heteroatoms independently selected from N, O and S, which ring is optionally substituted by groups Q¹ and Q²;

Q¹ is halogen, hydroxy, C₁₋₆alkyl, C₁₋₆alkoxy, aryl, heteroaryl, CONR^(a)R^(b), (CH₂)₀₋₃NR^(a)R^(b), O(CH₂)₁₋₃NR^(a)R^(b), O(CH₂)₀₋₃CONR^(a)R^(b), O(CH₂)₀₋₃aryl, O(CH₂)₀₋₃heteroaryl, O(CR^(e)R^(f))aryl, O(CR^(e)R^(f))heteroaryl or OCHR^(c)R^(d);

R^(a) and R^(b) are each independently selected from hydrogen, C₁₋₄alkyl and C(O)C₁₋₄alkyl;

or R^(a), R^(b) and the nitrogen atom to which they are attached form a heteroaliphatic ring of 4 to 7 ring atoms, where said ring is optionally substituted by halogen, hydroxy, C₁₋₄alkyl or C₁₋₄alkoxy;

R^(c) and R^(d) are each independently selected from hydrogen and C₁₋₄alkoxy;

or R^(c) and R^(d) are linked by a heteroatom selected from N, O and S to form a heteroaliphatic ring of 4 to 7 ring atoms, where said ring is optionally substituted by halogen, hydroxy, C₁₋₄alkyl or C₁₋₄alkoxy;

and wherein said C₁₋₄alkyl, C₁₋₄alkoxy and aryl groups are optionally substituted by halogen or hydroxy;

R^(e) is hydrogen or C₁₋₆alkyl;

R^(f) is C₁₋₆alkyl;

Q² is halogen, hydroxy, C₁₋₄alkyl or C₁₋₄alkoxy, where said C₁₋₄alkyl and C₁₋₄alkoxy groups are optionally substituted by halogen or hydroxy;

or Q¹ and Q² may be linked by a bond or a heteroatom selected from N, O and S to form a ring of 4 to 7 atoms, where said ring is optionally substituted by halogen, hydroxy, C₁₋₄alkyl or C₁₋₄alkoxy;

A is C₃₋₆alkyl or C₂₋₆alkenyl,

or A is a non-aromatic ring of 3 to 8 ring atoms where said ring may contain a double bond and/or may contain a O, S, SO, SO₂ or NH moiety,

or A is a non-aromatic bicyclic moiety of 4 to 8 ring atoms,

and A is optionally substituted by halogen, hydroxy, C₁₋₄alkyl or C₁₋₄alkoxy;

D is N or CR⁹;

R^(g) is hydrogen, fluorine, chlorine, C₁₋₄alkyl, C₂₋₄alkenyl or C₁₋₄alkoxy, where said C₁₋₄alkyl, C₂₋₄alkenyl and C₁₋₄alkoxy groups are optionally substituted by hydroxy or fluorine;

W is a bond, C═O, O, S(O)₀₋₂ or —(CR¹⁰R¹¹)—(CR¹²R¹³)₀₋₁—;

X is C═O, O, —CR¹⁴R¹⁵— or NR¹⁴;

R¹⁰, R¹¹, R¹², R¹³, R¹⁴ and R¹⁵ are each independently selected from hydrogen, hydroxy, C₁₋₆alkyl, C₂₋₆alkenyl, C₁₋₆alkoxy, C(O)C₁₋₆alkyl, (CH₂)₀₋₃aryl, (CH₂)₀₋₃heteroaryl, (CH₂)₀₋₃Het, (CH₂)₀₋₃NR¹⁶R¹⁷, C(O)(CH₂)₀₋₃NR¹⁶R¹⁷, NHC(O)(CH₂)₀₋₃NR¹⁶R¹⁷, O(CH₂)₁₋₃NR¹⁶R¹⁷, S(O)₀₋₂(CH₂)₀₋₃R¹⁶R¹⁷ and C(O)(CH₂)₀₋₃OR¹⁶;

or R¹⁴ is linked to R² or R²³ to form a ring of 4 to 10 atoms, where said ring is optionally substituted by halogen, hydrogen, C₁₋₄alkyl or C₁₋₄alkoxy;

Het is a heteroaliphatic ring of 4 to 7 ring atoms, which ring may contain 1, 2 or 3 heteroatoms selected from N, O or S or a group S(O), S(O)₂, NH or NC₁₋₄alkyl;

R¹⁶ and R¹⁷ are independently selected from hydrogen, C₁₋₆alkyl and (CH₂)₀₋₄NR¹⁸R¹⁹;

or R¹⁶, R¹⁷ and the nitrogen atom to which they are attached form a heteroaliphatic ring of 4 to 7 ring atoms, which ring may optionally contain 1 or 2 more heteroatoms selected from O or S or a group S(O), S(O)₂, NH or NC₁₋₄alkyl, and which ring is optionally substituted by halogen, hydroxy, C₁₋₄alkyl or C₁₋₄alkoxy;

R¹⁸ and R¹⁹ are independently selected from hydrogen and C₁₋₆alkyl; or R¹⁸, R¹⁹ and the nitrogen atom to which they are attached form a heteroaliphatic ring of 4 to 7 ring atoms, which ring may optionally contain 1 or 2 more heteroatoms selected from O or S or a group S(O), S(O)₂, NH or NC₁₋₄alkyl, and which ring is optionally substituted by halogen, hydroxy, C₁₋₄alkyl or C₁₋₄alkoxy;

R¹ is hydrogen or C₁₋₆alkyl;

B is —CR²⁰R²¹—, —C(═O)—, —SO— or —SO₂—;

R²⁰ and R²¹ are independently selected from hydrogen and C₁₋₆alkyl; or R²⁰ and R²¹, together with the carbon atom to which they are joined, form a C₃₋₆cycloalkyl group;

M is C₄₋₈alkylene or C₄₋₈alkenylene, optionally substituted by R²², where 1, 2 or 3 of the carbon atoms in the C₄₋₈alkylene or C₄₋₈alkenylene groups is optionally replaced by O, NR²³, S, SO, SO₂, aryl, heteroaryl or Het,

where R²³ is hydrogen or C₁₋₆alkyl,

or R²³ is linked to R¹⁴ to form a ring of 4 to 10 atoms as hereinbefore described;

where R²² is halo, C₁₋₄alkyl, (CH₂)₀₋₃C₃₋₈cycloalkyl, (CH₂)₀₋₃aryl, heteroaryl, Het or oxo,

or R²² is linked to R¹⁴ to form a ring of 4 to 10 atoms as hereinbefore described;

and pharmaceutically acceptable salts thereof.

DETAILED DESCRIPTION OF THE INVENTION

In one embodiment of the present invention, Ar is a five- or six-membered aromatic ring optionally containing 1, 2 or 3 heteroatoms independently selected from N, O and S, and which ring is optionally substituted by groups Q¹ and Q² as hereinbefore defined.

Preferably, Ar is a five- or six-membered aromatic ring optionally containing 1 or 2 heteroatoms independently selected from N, O or S, such as phenyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, furanyl, pyrazolyl, imidazolyl and thienyl, which ring is optionally substituted by groups Q¹ and Q² as hereinbefore defined. More preferably, Ar is phenyl, 2-pyridyl, 3-pyridyl, 4-pyridyl, 2-furanyl or 3-furanyl, particularly phenyl, optionally substituted by groups Q¹ and Q² as hereinbefore defined.

Preferably, Q¹ is halogen, hydroxy, C₁₋₄alkyl or C₁₋₄alkoxy. More preferably, Q¹ is fluorine, chlorine, methyl or methoxy. Most preferably, Q¹ is methoxy.

Preferably, Q² is absent.

In a further embodiment, A is C₃₋₆alkyl, C₂₋₆alkenyl or C₃₋₈cycloalkyl, where A is optionally substituted by halogen, hydroxy, C₁₋₄alkyl or C₁₋₄alkoxy. Preferably, A is C₃₋₈cycloalkyl, more preferably cyclopentyl or cyclohexyl, most preferably cyclohexyl, optionally substituted by halogen, hydroxy, C₁₋₄alkyl or C₁₋₄alkoxy.

Preferably, A is unsubstituted or substituted by fluorine, chlorine, methyl or methoxy, particularly fluorine. More preferably, A is unsubstituted.

In a further embodiment, D is CR^(g) where R^(g) is as hereinbefore defined. Preferably, R^(g) is hydrogen or C₁₋₄alkyl. More preferably, R^(g) is hydrogen.

In a further embodiment, W is a bond, C═O or —(CR¹⁰R¹¹)—(CR¹²R¹³)₀₋₁— where R¹⁰, R¹¹, R¹² and R¹³ are as hereinbefore defined. Preferably, W is —(CR¹⁰R¹¹)—(CR¹²R¹³)₀₋₁—. More preferably, W is —CH₂— or —CH₂CH₂—. Most preferably, W is —CH₂—.

In a further embodiment, X is C═O or —CR¹⁴R¹⁵, where R¹⁴ and R¹⁵ are as hereinbefore defined. Preferably, X is C═O or —CH₂—.

In a further embodiment, R¹ is hydrogen or methyl. Preferably, R¹ is hydrogen.

In a further embodiment, B is —CH₂— or —SO₂—. Preferably, B is —SO₂—.

In a further embodiment, M is C₄₋₈alkylene, optionally substituted by halo, C₁₋₄alkyl or oxo, where 1 or 2 of the carbon atoms in the C₄₋₈alkylene group is optionally replaced by O, NR²³, S, SO or SO₂, where R²³ is as hereinbefore defined. Preferably, M is C₅₋₈alkylene, optionally substituted by C₁₋₄alkyl or oxo, where 1 or 2 of the carbon atoms in the C₅₋₈alkylene group is replaced by O, NH or N(C₁₋₄alkyl). Examples of suitable M groups include:

In one embodiment of the present invention, there is provided the compound of formula (Ia):

or a pharmaceutically acceptable salt thereof, wherein W, X and M are as defined in relation to formula (I).

When any variable occurs more than one time in formula (I) or in any substituent, its definition on each occurrence is independent of its definition at every other occurrence.

As used herein, the term “alkyl” or “alkoxy” as a group or part of a group means that the group is straight or branched. Examples of suitable alkyl groups include methyl, ethyl, n-propyl, i-propyl, n-butyl, s-butyl and t-butyl. Examples of suitable alkoxy groups include methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, s-butoxy and t-butoxy.

The cycloalkyl groups referred to herein may represent, for example, cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl.

As used herein, the term “alkenyl” and “alkynyl” as a group or part of a group means that the group is straight or branched. Examples of suitable alkenyl groups include vinyl and allyl. A suitable alkynyl group is propargyl.

As used herein, the term “alkylene” means that the alkyl group links two separate groups and may be straight or branched. Examples of suitable alkylene groups include ethylene [—CH₂—CH₂—] and propylene [—CH₂—CH₂—CH₂—, —CH(CH₃)—CH₂— or —CH₂—CH(CH₃)—]. The terms “alkenylene” and “alkynylene” shall be construed in an analogous manner.

When used herein, the term “halogen” means fluorine, chlorine, bromine and iodine.

When used herein, the term “aryl” as a group or part of a group means a carbocyclic aromatic ring. Examples of suitable aryl groups include phenyl and naphthyl.

When used herein, the term “heteroaryl” as a group or part of a group means a 5- to 10-membered heteroaromatic ring system containing 1 to 4 heteroatoms selected from N, O and S. Particular examples of such groups include pyrrolyl, furanyl, thienyl, pyridyl, pyrazolyl, imidazolyl, oxazolyl, isoxazolyl, thiazolyl, isothiazolyl, pyrazinyl, pyrimidinyl, pyridazinyl, triazolyl, oxadiazolyl, thiadiazolyl, triazinyl, tetrazolyl, indolyl, benzothienyl, benzimidazolyl, benzofuryl, quinolinyl and isoquinolinyl.

Where a compound or group is described as “optionally substituted” one or more substituents may be present. Furthermore, optional substituents may be attached to the compounds or groups which they substitute in a variety of ways, either directly or through a connecting group of which the following are examples: amine, amide, ester, ether, thioether, sulfonamide, sulfamide, sulfoxide, urea, thiourea and urethane. As appropriate an optional substituent may itself be substituted by another substituent, the latter being connected directly to the former or through a connecting group such as those exemplified above.

Specific compounds within the scope of this invention include:

-   101:     16-cyclohexyl-3,6-dimethyl-17-phenyl-4,5,6,7,8,9-hexahydro-1H-13,15-(ethanediylidene)pyrrolo[2,1-f][1,2,7,10,13]thiatetraazacyclohexadecine-2,12(3H)-dione     10,10-dioxide, -   201:     17-cyclohexyl-3,6-dimethyl-18-phenyl-3,4,5,6,7,8,9,10-octahydro-14,16-(ethanediylidene)pyrrolo[2,1-f][1,2,7,10,13]thiatetraazacycloheptadecine-2,13-dione     11,11-dioxide,     and pharmaceutically acceptable salts thereof.

For use in medicine, the salts of the compounds of formula (I) will be non-toxic pharmaceutically acceptable salts. Other salts may, however, be useful in the preparation of the compounds according to the invention or of their non-toxic pharmaceutically acceptable salts. Suitable pharmaceutically acceptable salts of the compounds of this invention include acid addition salts which may, for example, be formed by mixing a solution of the compound according to the invention with a solution of a pharmaceutically acceptable acid such as hydrochloric acid, fumaric acid, p-toluenesulfonic acid, maleic acid, succinic acid, acetic acid, citric acid, tartaric acid, carbonic acid, phosphoric acid or sulfuric acid. Salts of amine groups may also comprise quaternary ammonium salts in which the amino nitrogen atom carries a suitable organic group such as an alkyl, alkenyl, alkynyl or aralkyl moiety. Furthermore, where the compounds of the invention carry an acidic moiety, suitable pharmaceutically acceptable salts thereof may include metal salts such as alkali metal salts, e.g. sodium or potassium salts; and alkaline earth metal salts, e.g. calcium or magnesium salts.

The salts may be formed by conventional means, such as by reacting the free base form of the product with one or more equivalents of the appropriate acid in a solvent or medium in which the salt is insoluble, or in a solvent such as water which is removed in vacuo or by freeze drying or by exchanging the anions of an existing salt for another anion on a suitable ion exchange resin.

The present invention includes within its scope prodrugs of the compounds of formula (I) above. In general, such prodrugs will be functional derivatives of the compounds of formula (I) which are readily convertible in vivo into the required compound of formula (I). Conventional procedures for the selection and preparation of suitable prodrug derivatives are described, for example, in “Design of Prodrugs”, ed. H. Bundgaard, Elsevier, 1985.

A prodrug may be a pharmacologically inactive derivative of a biologically active substance (the “parent drug” or “parent molecule”) that requires transformation within the body in order to release the active drug, and that has improved delivery properties over the parent drug molecule. The transformation in vivo may be, for example, as the result of some metabolic process, such as chemical or enzymatic hydrolysis of a carboxylic, phosphoric or sulfate ester, or reduction or oxidation of a susceptible functionality.

The present invention includes within its scope solvates of the compounds of formula (I) and salts thereof, for example, hydrates.

The present invention also includes within its scope any enantiomers, diastereomers, geometric isomers and tautomers of the compounds of formula (I). It is to be understood that all such isomers and mixtures thereof are encompassed within the scope of the invention.

The present invention further provides a compound of formula (I) or a pharmaceutically acceptable salt thereof for use in therapy.

In another aspect, the invention provides the use of a compound of formula (I) as defined above, or a pharmaceutically acceptable salt thereof, for the manufacture of a medicament for treatment or prevention of infection by hepatitis C virus in a human or animal.

A further aspect of the invention provides a pharmaceutical composition comprising a compound of formula (I) as defined above, or a pharmaceutically acceptable salt thereof, in association with a pharmaceutically acceptable carrier. The composition may be in any suitable form, depending on the intended method of administration. It may for example be in the form of a tablet, capsule or liquid for oral administration, or of a solution or suspension for administration parenterally.

The pharmaceutical compositions optionally also include one or more other agents for the treatment of viral infections such as an antiviral agent, or an immunomodulatory agent such as α-, β- or γ-interferon.

In a further aspect, the invention provides a method of inhibiting hepatitis C virus polymerase and/or of treating or preventing an illness due to hepatitis C virus, the method involving administering to a human or animal (preferably mammalian) subject suffering from the condition a therapeutically or prophylactically effective amount of the pharmaceutical composition described above or of a compound of formula (I) as defined above, or a pharmaceutically acceptable salt thereof. “Effective amount” means an amount sufficient to cause a benefit to the subject or at least to cause a change in the subject's condition.

The dosage rate at which the compound is administered will depend on a variety of factors including the activity of the specific compound employed, the metabolic stability and length of action of that compound, the age of the patient, body weight, general health, sex, diet, mode and time of administration, rate of excretion, drug combination, the severity of the particular condition and the host undergoing therapy. Suitable dosage levels may be of the order of 0.02 to 5 or 10 g per day, with oral dosages two to five times higher. For instance, administration of from 1 to 50 mg of the compound per kg of body weight from one to three times per day may be in order. Appropriate values are selectable by routine testing. The compound may be administered alone or in combination with other treatments, either simultaneously or sequentially. For instance, it may be administered in combination with effective amounts of antiviral agents, immunomodulators, anti-infectives or vaccines known to those of ordinary skill in the art. It may be administered by any suitable route, including orally, intravenously, cutaneously and subcutaneously. It may be administered directly to a suitable site or in a manner in which it targets a particular site, such as a certain type of cell. Suitable targeting methods are already known.

An additional aspect of the invention provides a method of preparation of a pharmaceutical composition, involving admixing at least one compound of formula (I) as defined above, or a pharmaceutically acceptable salt thereof, with one or more pharmaceutically acceptable adjuvants, diluents or carriers and/or with one or more other therapeutically or prophylactically active agents.

The present invention also provides a process for the preparation of compounds of formula (I).

According to a general process (a), compounds of formula (I) may be prepared by internal ring closure of the compound of formula (II):

where A, Ar, B, D, R¹, W and X are as defined in relation to formula (I), and M′ and M″ have suitable precursor functionality to form group M as defined in relation to formula (I). For instance, when M is —CH₂—CH₂—CH₂—N(CH₃)—CH₂—CH₂—N(CH₃)—, M′ can be —CH₂—CH₂—CH₂Cl and M″ can be —N(CH₃)—CH₂—CH₂—NH(CH₃), where the reaction is carried out in the presence of a mild base, such as diisopropylethylamine, in a suitable solvent, such as DMF, under microwave irradiation.

Compounds of formula (II) are either known in the art or may be prepared by conventional methodology well known to one of ordinary skill in the art using, for instance, procedures described in the accompanying Descriptions and Examples, or by alternative procedures which will be readily apparent.

General Synthetic Schemes

Two general strategies were employed for assembly of compounds from the untethered macrocyclic class (Methods A and B); Method B can be regarded as an extension of Method A.

A suitably C2/C3 functionalised indole-6-carboxylate was assembled first (as described in published International applications WO 2004/087714 and WO 2006/029912). B′, W′ and X′ are suitable precursor functionality to groups B, W and X respectively as defined in relation to formula (I). A precursor fragment to one section of the macrocycle was installed on the indole N, with subsequent unmasking of the acid at C6 and functionalisation to introduce a precursor fragment to the remaining segment of the macrocycle. Functional group manipulation and macrocyclisation (e.g., via amide bond formation, alkylation, reductive amination, metathesis etc.) set up the macrocycle. Potentially, the bond formed in ring closure can be at almost any point around the macrocyclic linker (e.g., forming the acylsulfonamide bond could also be the ring closing step).

B′, M′, W′ and X′ have suitable precursor functionality to groups B, M, W and X respectively as defined in relation to formula (I). Functional groups on the macrocycle were manipulated post-closure, e.g., via reductive amination, alkylation, amide reduction, amide formation, etc. Potentially, sidechains can branch from any point around the macrocyclic linker.

During any of the above synthetic sequences it may be necessary and/or desirable to protect sensitive or reactive groups on any of the molecules concerned. This may be achieved by means of conventional protecting groups, such as those described in Protective Groups in Organic Chemistry, ed. J. F. W. McOmie, Plenum Press, 1973; and T. W. Greene & P. G. M. Wuts, Protective Groups in Organic Synthesis, John Wiley & Sons, 3rd edition, 1999. The protecting groups may be removed at a convenient subsequent stage using methods known from the art.

The present invention is illustrated further by the following non-limiting examples.

The compounds of the invention were tested for inhibitory activity against the HCV RNA dependent RNA polymerase (NS5B) in an enzyme inhibition assay (example (i)) and in a cell based sub-genomic replication assay (example (ii)). The compounds generally have IC50's below 1 μM in the enzyme assay and several examples have EC50's below 5 μM in the cell based assay.

Compound names in the examples were generated using software from ACDLabs (version 8.0).

(i) In-Vitro HCV NS5B Enzyme Inhibition Assay

WO 96/37619 describes the production of recombinant HCV RdRp from insect cells infected with recombinant baculovirus encoding the enzyme. The purified enzyme was shown to possess in vitro RNA polymerase activity using RNA as template. The reference describes a polymerisation assay using poly(A) and oligo(U) as a primer or an heteropolymeric template. Incorporation of tritiated UTP or NTPs is quantified by measuring acid-insoluble radioactivity. The present inventors have employed this assay to screen the various compounds described above as inhibitors of HCV RdRp.

Incorporation of radioactive UMP was measured as follows. The standard reaction (50 μl) was carried out in a buffer containing 20 mM tris/HCl pH 7.5, 5 mM MgCl₂, 1 mM DTT, 50 mM NaCl, 0.03% N-octylglucoside, 1 μCi [³H]-UTP (40 Ci/mmol, NEN), 10 μM UTP and 10 μg/ml poly(A) or 5 μM NTPs and 5 μg/ml heteropolymeric template. Oligo(U)₁₂ (1 μg/ml, Genset) was added as a primer in the assay working on Poly(A) template. The final NS5B enzyme concentration was 5 nM. The order of assembly was: 1) compound, 2) enzyme, 3) template/primer, 4) NTP. After 1 h incubation at 22° C. the reaction was stopped by adding 50 μl of 20% TCA and applying samples to DE81 filters. The filters were washed thoroughly with 5% TCA containing 1M Na₂HPO₄/NaH₂PO₄, pH 7.0, rinsed with water and then ethanol, air dried, and the filter-bound radioactivity was measured in the scintillation counter. Carrying out this reaction in the presence of various concentrations of each compound set out above allowed determination of IC₅₀ values by utilising the formula: % Residual activity=100/(1+[I]/IC₅₀)^(s) where [I] is the inhibitor concentration and “s” is the slope of the inhibition curve. (ii) Cell Based HCV Replication Assay

Cell clones that stably maintain subgenomic HCV replicon were obtained by transfecting Huh-7 cells with an RNA replicon identical to I₃₇₇neo/NS3-3′/wt described by Lohmann et al. (1999) (EMBL-GENBANK No. AJ242652), followed by selection with neomycin sulfate (G418). Viral replication was monitored by measuring the expression of the NS3 protein by an ELISA assay performed directly on cells grown in 96 wells microtiter plates (Cell-ELISA) using the anti-NS3 monoclonal antibody 10E5/24 (as described in published International application WO 02/59321). Cells were seeded into 96 well plates at a density of 10⁴ cells per well in a final volume of 0.1 ml of DMEM/10% FCS. Two hours after plating, 50 μl of DMEM/10% FCS containing a 3× concentration of inhibitor were added, cells were incubated for 96 hours and then fixed for 10′ with ice-cold isopropanol. Each condition was tested in duplicate and average absorbance values were used for calculations. The cells were washed twice with PBS, blocked with 5% non-fat dry milk in PBS+0.1% TRITON X100+0.02% SDS (PBSTS) and then incubated o/n at 4° C. with the 10E5/24 mab diluted in Milk/PBSTS. After washing 5 times with PBSTS, the cells were incubated for 3 hours at room temperature with Fc specific anti-mouse IgG conjugated to alkaline phosphatase (Sigma), diluted in Milk/PBSTS. After washing again as above, the reaction was developed with p-Nitrophenyl phosphate disodium substrate (Sigma) and the absorbance at 405/620 nm read at intervals. For calculations, we used data sets where samples incubated without inhibitors had absorbance values comprised between 1 and 1.5. The inhibitor concentration that reduced by 50% the expression of NS3 (IC₅₀) was calculated by fitting the data to the Hill equation, Fraction inhibition=1−(Ai−b)/(A ₀ −b)=[I] ^(n)([I] ^(n) +IC ₅₀) where:

-   -   Ai=absorbance value of HBI10 cells supplemented with the         indicated inhibitor concentration.     -   A₀=absorbance value of HBI10 cells incubated without inhibitor.     -   b=absorbance value of Huh-7 cells plated at the same density in         the same microtiter plates and incubated without inhibitor.     -   n=Hill coefficient.         (iii) General Procedures

All solvents were obtained from commercial sources (Fluka, puriss.) and were used without further purification. With the exception of routine deprotection and coupling steps, reactions were carried out under an atmosphere of nitrogen in oven dried (110° C.) glassware. Organic extracts were dried over sodium sulfate, and were concentrated (after filtration of the drying agent) on rotary evaporators operating under reduced pressure. Flash chromatography was carried out on silica gel following published procedure (W. C. Still et al., J. Org. Chem. 1978, 43, 2923) or on commercial flash chromatography systems (BIOTAGE Corporation and JONES FLASHMASTER II) utilising pre-packed columns.

Reagents were usually obtained directly from commercial suppliers (and used as supplied) but a limited number of compounds from in-house corporate collections were utilised. In the latter case the reagents are readily accessible using routine synthetic steps that are either reported in the scientific literature or are known to those skilled in the art.

¹H NMR spectra were recorded on BRUKER AM series spectrometers operating at (reported) frequencies between 300 and 600 MHz. Chemical shifts (δ) for signals corresponding to non-exchangeable protons (and exchangeable protons where visible) are recorded in parts per million (ppm) relative to tetramethylsilane and are measured using the residual solvent peak as reference. Signals are tabulated in the order: multiplicity (s, singlet; d, doublet; t, triplet; q, quartet; m, multiplet; br, broad, and combinations thereof); coupling constant(s) in hertz (Hz); number of protons. Mass spectral (MS) data were obtained on a PERKIN ELMER API 100, or WATERS MICROMASS ZQ, operating in negative (ES⁻) or positive (ES⁺) ionization mode and results are reported as the ratio of mass over charge (m/z) for the parent ion only. Preparative scale HPLC separations were carried out on a WATERS DELTA PREP 4000 separation module, equipped with a WATERS 486 absorption detector or on a GILSON preparative system. In all cases compounds were eluted with linear gradients of water and acetonitrile both containing 0.1% TFA using flow rates between 15 and 40 mL/min.

The following abbreviations are used in the examples, the schemes and the tables: Ac: acetyl; aq.: aqueous; Ar: aryl; atm: atmosphere; cat.: catalytic; dioxan(e): 1,4-dioxane; dppf: (1,1′-bisdiphenylphosphino)ferrocene; 1,2-DCE: 1,2-dichloroethane; DCM: dichloromethane; DIPEA: diisopropylethyl amine; DMAP: N,N-dimethylpyridin-4-amine; DME: dimethoxyethane; DMF: dimethylformamide; DMS: dimethylsulfide; DMSO: dimethylsulfoxide; DMP: Dess-Martin Periodinane; EDAC.HCl: 1-ethyl-(3-dimethylaminopropyl)carbodiimide HCl salt; eq.: equivalent(s); Et₃N: triethylamine; EtOAc: ethyl acetate; Et₂O: diethyl ether; EtOH: ethanol; Et₃SiH: triethylsilane; FC: Flash Chromatography; h: hour(s); HOAc: acetic acid; HATU: O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophophate; Me: methyl; MeCN: acetonitrile; MeOH: methanol; min: minutes; MS: mass spectrum; NBS: N-bromo succinimide; PE: petroleum ether; Ph: phenyl; quant.: quantitative; RP-HPLC: reversed phase high-pressure liquid chromatography; RT: room temperature; sat.: saturated; sec: second(s); SFC: Super-critical fluid chromatography; s.s.: saturated solution; TBAF: tetrabutyl ammonium fluoride; TBTU: O-benzotriazol-1-yl-N,N,N′,N′-tetramethyluronium tetrafluoroborate; TFA: trifluoroacetic acid; THF: tetrahydrofuran; THP: tetrahydropyranyl; TMS: trimethylsilyl.

Example 1 16-cyclohexyl-3,6-dimethyl-17-phenyl-4,5,6,7,8,9-hexahydro-1H-13,15-(ethanediylidene)pyrrolo[2,1-f][1,2,7,10,13]thiatetraazacyclohexadecine-2,12(3H)-dione 10,10-dioxide Step 1: methyl 2-bromo-1-(2-tert-butoxy-2-oxoethyl)-3-cyclohexyl-1H-indole-6-carboxylate

A solution of methyl 2-bromo-3-cyclohexyl-1H-indole-6-carboxylate (prepared as described in published International patent application WO 2004/087714, from commercially available methyl indole-6-carboxylate) in DMF (0.1 M) was treated with NaH (60% dispersion in mineral oil) (2 eq) at 0° C. The reaction was allowed to reach RT under a nitrogen atmosphere. Then tert-butyl-bromo acetate (3 eq) was added and the reaction was heated to 60° C. for 3 h. The reaction mixture was allowed to cool to RT, diluted with EtOAc and washed with an aqueous solution of HCl (1N), brine and dried over Na₂SO₄ before being filtered and the solvent volume reduced in vacuo. The product precipitated from the residual solvent. The solid was collected and dried in vacuo to afford the title compound (95%). (ES⁺) m/z 450 (M+H)⁺, 452 (M+H)⁺

Step 2: methyl 1-(2-tert-butoxy-2-oxoethyl)-3-cyclohexyl-2-phenyl-1H-indole-6-carboxylate

To a solution of methyl 2-bromo-1-(2-tert-butoxy-2-oxoethyl)-3-cyclohexyl-1H-indole-6-carboxylate in dioxane (0.06 M) was added bis(triphenylphosphine)palladium(II) dichloride (0.2 eq) at RT under a nitrogen atmosphere. Then aqueous Na₂CO₃ (2 M; 4 eq) followed by phenylboronic acid (2.5 eq) were added and the reaction was heated to 80° C. for 2 h. The reaction mixture was allowed to cool and concentrated in vacuo. DCM was added and the organic phase washed with H₂O, brine and dried over Na₂SO₄ before being filtered and concentrated in vacuo. The crude material was purified by automated FC (SiO₂; 95:5 EtOAc/PE) to afford the title compound (88%). (ES⁺) m/z 448 (M+H)⁺

Step 3: [3-cyclohexyl-6-(methoxycarbonyl)-2-phenyl-1H-indol-1-yl]acetic acid

To methyl 1-(2-tert-butoxy-2-oxoethyl)-3-cyclohexyl-2-phenyl-1H-indole-6-carboxylate in DCM/H₂O (2:1; 0.15 M), TFA (>300 eq) were added at RT and the reaction left stirring for 1 h. The volatiles were removed in vacuo, and the residue diluted with DCM. The organic phase was washed with brine, dried over Na₂SO₄, filtered and the solvent evaporated in vacuo to afford the title compound (98%). (ES⁺) m/z 392 (M+H)⁺

Step 4: methyl 1-{2-[{2-[(tert-butoxycarbonyl)(methyl)amino]ethyl}(methyl)amino]-2-oxoethyl}-3-cyclohexyl-2-phenyl-1H-indole-6-carboxylate

To a solution of [3-cyclohexyl-6-(methoxycarbonyl)-2-phenyl-1H-indol-1-yl]acetic acid in DCM (0.04 M), DIPEA (3 eq), tert-butyl methyl[2-(methylamino)ethyl]carbamate (2 eq) (prepared as described in European patent application EP0296811, from commercially available N,N-dimethylethylenediamine) and HATU (2 eq) were added and the mixture stirred at RT for 2 h. The solution was diluted with DCM and washed with a saturated aqueous solution of NH₄Cl, a saturated aqueous solution of NaHCO₃ and brine before being dried over Na₂SO₄, filtered and concentrated in vacuo. The crude was then used in the next step without any further purification. (ES⁺) m/z 562 (M+H)⁺

Step 5: 1-{2-[{2-[(tert-butoxycarbonyl)(methyl)amino]ethyl}(methyl)amino]-2-oxoethyl}-3-cyclohexyl-2-phenyl-1H-indole-6-carboxylic acid

The crude methyl 1-{2-[{2-[(tert-butoxycarbonyl)(methyl)amino]ethyl}(methyl)amino]-2-oxoethyl}-3-cyclohexyl-2-phenyl-1H-indole-6-carboxylate in dioxane/H₂O/MeOH solution (1:1:1; 0.06 M) was treated with an aqueous solution of KOH (5N) (3 eq). The solution was stirred at 60° C. for 4 h. The volume of the solution was reduced in vacuo, and the mixture acidified with HCl (1N) before extracting with EtOAc (2×). The combined organic fractions were washed with brine, before being dried over Na₂SO₄, filtered and concentrated in vacuo. The crude was then used in the next step without any further purification. (ES⁺) m/z 548 (M+H)⁺

Step 6: N-benzyl-3-chloropropane-1-sulfonamide

3-chloro-propylsulfonyl chloride was added dropwise to a stirred solution of benzylamine (1 eq) and triethylamine (1.1 eq) in DCM (0.6 M) at 0° C. The solution was stirred at RT overnight. The solvent was then removed in vacuo, Et₂O was added to get a precipitate that was eliminated by filtration, while the filtrate was concentrated in vacuo. Subsequent addition of PE resulted in the formation of a white precipitate that was collected by filtration to afford the title compound (86%). ¹H NMR (400 MHz, DMSO-d₆, 300 K) δ 2.02-2.09 (m, 2H), 3.03-3.07 (m, 2H), 3.67 (t, J 6.6, 2H), 4.14 (d, J 6.1, 2H), 7.25-7.30 (m, 1H), 7.32-7.36 (m, 4H), 7.73 (t, J 6.1, 1H).

Step 7: tert-butyl {2-[{[6-({benzyl[(3-chloropropyl)sulfonyl]amino}carbonyl)-3-cyclohexyl-2-phenyl-1H-indol-1-yl]acetyl}(methyl)amino]ethyl}methylcarbamate

A solution of the crude 1-{2-[{2-[(tert-butoxycarbonyl)(methyl)amino]ethyl}(methyl)amino]-2-oxoethyl}-3-cyclohexyl-2-phenyl-1H-indole-6-carboxylic acid in DCM (0.04 M) was treated with DMAP (2.5 eq), N-benzyl-3-chloropropane-1-sulfonamide (1.5 eq) and EDAC.HCl (1.5 eq). The reaction was left stirring at 40° C. overnight. Further DMAP (2.5 eq), N-benzyl-3-chloropropane-1-sulfonamide (1.5 eq) and EDAC.HCl (1.5 eq) were added and the reaction left to stir at 40° C. for another night. The mixture was diluted with DCM and washed with an aqueous solution of HCl (1N), a saturated aqueous solution of NaHCO₃ and brine before being dried over Na₂SO₄, filtered and concentrated in vacuo. The crude was then used in the next step without any further purification. (ES⁺) m/z 777 (M+H)⁺

Step 8: N-benzyl-N-[(3-chloropropyl)sulfonyl]-3-cyclohexyl-1-(2-{methyl[2-(methylamino)ethyl]amino}-2-oxoethyl)-2-phenyl-1H-indole-6-carboxamide hydrochloride

A solution of the crude tert-butyl {2-[{[6-({benzyl[(3-chloropropyl)sulfonyl]amino}carbonyl)-3-cyclohexyl-2-phenyl-1H-indol-1-yl]acetyl}(methyl)amino]ethyl}methylcarbamate in DCM) (0.09 M) was treated with TFA (140 eq) at 0° C. The reaction was allowed to reach RT in about 1 h. The solvent was then removed in vacuo, a 2 M solution HCl in Et₂O was added and the volatiles removed in vacuo. Acetonitrile was added and the precipitate was collected by filtration to afford clean compound (30%). (ES⁺) m/z 677 (M+H)⁺

Step 9: 16-cyclohexyl-3,6-dimethyl-17-phenyl-4,5,6,7,8,9-hexahydro-1H-13,15-(ethanediylidene)pyrrolo[2,1-f][1,2,7,10,13]thiatetraazacyclohexadecine-2,12(3H)-dione 10,10-dioxide

DIPEA (40 eq) was added to N-benzyl-N-[(3-chloropropyl)sulfonyl]-3-cyclohexyl-1-(2-{methyl[2-(methylamino)ethyl]amino}-2-oxoethyl)-2-phenyl-1H-indole-6-carboxamide hydrochloride in DMF (0.007 M). The reaction mixture was heated in a microwave system at 180° C. for 2800 s. Then 10% Pd/C, (1:1 weight:weight with respect to substrate) was added and the reaction stirred under a hydrogen atmosphere overnight. The reaction was flushed with N₂, filtered and concentrated in vacuo. The crude was then purified by automated RP-HPLC (stationary phase: column SYMMETRY PREP. C18, 7 μm, 19×300 mm. Mobile phase: acetonitrile/H₂O buffered with 0.1% TFA). Fractions containing the pure compound were combined and freeze dried to afford the title compound as a white powder (24%). ¹H NMR (500 MHz, DMSO-d₆+TFA, 292 K) δ 1.16-1.32 (m, 3H), 1.64-2.11 (m, 9H), 2.57-2.60 (m, 1H), 2.84 (s, 3H), 3.12 (s, 3H), 3.19-3.31 (m, 4H), 3.44-3.60 (m, 3H), 3.73-3.82 (m, 1H), 4.82-4.92 (m, 2H), 7.23-7.42 (m, 2H), 7.43-7.61 (m, 4H), 7.86-7.91 (m, 2H), 8.90-9.11 (b s, 1H); (ES⁺) m/z 551 (M+H)⁺

The following tables contain further examples:

TABLE 1 16-membered macrocycles Example m/z no. Compound name Structure procedure (ES⁺) 1≡101 16-cyclohexyl-3,6-dimethyl-17- phenyl-4,5,6,7,8,9-hexahydro-1H- 13,15-(ethanediylidene)pyrrolo [2,1-f][1,2,7,10,13] thiatetraazacyclohexadecine- 2,12(3H)-dione 10,10-dioxide

B 551

TABLE 2 17-membered macrocycles Example m/z no. Compound name Structure procedure (ES⁺) 201 17-cyclohexyl-3,6-dimethyl-18- phenyl-3,4,5,6,7,8,9,10-octahydro- 14,16-(ethanediylidene)pyrrolo [2,1-f][1,2,7,10,13] thiatetraazacycloheptadecine-2,13- dione 11,11-dioxide

B 565 

1. A compound of the formula (I):

wherein Ar is a moiety containing at least one aromatic ring and possesses 5-, 6-, 9- or 10-ring atoms optionally containing 1, 2 or 3 heteroatoms independently selected from N, O and S, which ring is optionally substituted by groups Q¹ and Q²; Q¹ is halogen, hydroxy, C₁₋₆alkyl, C₁₋₆alkoxy, aryl, heteroaryl, CONR^(a)R^(b), (CH₂)₀₋₃NR^(a)R^(b), O(CH₂)₁₋₃NR^(a)R^(b), O(CH₂)₀₋₃CONR^(a)R^(b), O(CH₂)₀₋₃aryl, O(CH₂)₀₋₃heteroaryl, O(CR^(e)R^(f))aryl, O(CR^(e)R^(f))heteroaryl or OCHR^(c)R^(d); R^(a) and R^(b) are each independently selected from hydrogen, C₁₋₄alkyl and C(O)C₁₋₄alkyl; or R^(a), R^(b) and the nitrogen atom to which they are attached form a heteroaliphatic ring of 4 to 7 ring atoms, where said ring is optionally substituted by halogen, hydroxy, C₁₋₄alkyl or C₁₋₄alkoxy; R^(c) and R^(d) are each independently selected from hydrogen and C₁₋₄alkoxy; or R^(c) and R^(d) are linked by a heteroatom selected from N, O and S to form a heteroaliphatic ring of 4 to 7 ring atoms, where said ring is optionally substituted by halogen, hydroxy, C₁₋₄alkyl or C₁₋₄alkoxy; and wherein said C₁₋₄alkyl, C₁₋₄alkoxy and aryl groups are optionally substituted by halogen or hydroxy; R^(e) is hydrogen or C₁₋₆alkyl; R^(f) is C₁₋₆alkyl; Q² is halogen, hydroxy, C₁₋₄alkyl or C₁₋₄alkoxy, where said C₁₋₄alkyl and C₁₋₄alkoxy groups are optionally substituted by halogen or hydroxy; or Q¹ and Q² may be linked by a bond or a heteroatom selected from N, O and S to form a ring of 4 to 7 atoms, where said ring is optionally substituted by halogen, hydroxy, C₁₋₄alkyl or C₁₋₄alkoxy; A is C₃₋₆alkyl or C₂₋₆alkenyl, or A is a non-aromatic ring of 3 to 8 ring atoms where said ring may contain a double bond and/or may contain a O, S, SO, SO₂ or NH moiety, or A is a non-aromatic bicyclic moiety of 4 to 8 ring atoms, and A is optionally substituted by halogen, hydroxy, C₁₋₄alkyl or C₁₋₄alkoxy; D is N or CR⁹; R^(g) is hydrogen, fluorine, chlorine, C₁₋₄alkyl, C₂₋₄alkenyl or C₁₋₄alkoxy, where said C₁₋₄alkyl, C₂₋₄alkenyl and C₁₋₄alkoxy groups are optionally substituted by hydroxy or fluorine; W is a bond, C═O, O, S(O)₀₋₂ or —(CR¹⁰R¹¹)—(CR¹²R¹³)₀₋₁—; X is C═O, O, —CR¹⁴R¹⁵— or NR¹⁴; R¹⁰, R¹¹, R¹², R¹³, R¹⁴ and R¹⁵ are each independently selected from hydrogen, hydroxy, C₁₋₆alkyl, C₂₋₆alkenyl, C₁₋₆alkoxy, C(O)C₁₋₆alkyl, (CH₂)₀₋₃aryl, (CH₂)₀₋₃heteroaryl, (CH₂)₀₋₃Het, (CH₂)₀₋₃NR¹⁶R¹⁷, C(O)(CH₂)₀₋₃NR¹⁶R¹⁷, NHC(O)(CH₂)₀₋₃NR¹⁶R¹⁷, O(CH₂)₁₋₃NR¹⁶R¹⁷, S(O)₀₋₂(CH₂)₀₋₃R¹⁶R¹⁷ and C(O)(CH₂)₀₋₃OR¹⁶; or R¹⁴ is linked to R²² or R²³ to form a ring of 4 to 10 atoms, where said ring is optionally substituted by halogen, hydrogen, C₁₋₄alkyl or C₁₋₄alkoxy; Het is a heteroaliphatic ring of 4 to 7 ring atoms, which ring may contain 1, 2 or 3 heteroatoms selected from N, O or S or a group S(O), S(O)₂, NH or NC₁₋₄alkyl; R¹⁶ and R¹⁷ are independently selected from hydrogen, C₁₋₆alkyl and (CH₂)₀₋₄NR¹⁸R¹⁹; or R¹⁶, R¹⁷ and the nitrogen atom to which they are attached form a heteroaliphatic ring of 4 to 7 ring atoms, which ring may optionally contain 1 or 2 more heteroatoms selected from O or S or a group S(O), S(O)₂, NH or NC₁₋₄alkyl, and which ring is optionally substituted by halogen, hydroxy, C₁₋₄alkyl or C₁₋₄alkoxy; R¹⁸ and R¹⁹ are independently selected from hydrogen and C₁₋₆alkyl; or R¹⁸, R¹⁹ and the nitrogen atom to which they are attached form a heteroaliphatic ring of 4 to 7 ring atoms, which ring may optionally contain 1 or 2 more heteroatoms selected from O or S or a group S(O), S(O)₂, NH or NC₁₋₄alkyl, and which ring is optionally substituted by halogen, hydroxy, C₁₋₄alkyl or C₁₋₄alkoxy; R¹ is hydrogen or C₁₋₆alkyl; B is —CR²⁰R²¹—, —(C═O)—, —SO— or —SO₂—; R²⁰ and R²¹ are independently selected from hydrogen and C₁₋₆alkyl; or R²⁰ and R²¹, together with the carbon atom to which they are joined, form a C₃₋₆cycloalkyl group; M is C₄₋₈alkylene or C₄₋₈alkenylene, optionally substituted by R²², where 1, 2 or 3 of the carbon atoms in the C₄₋₈alkylene or C₄₋₈alkenylene groups is optionally replaced by O, NR²³, S, SO, SO₂, aryl, heteroaryl or Het, where R²³ is hydrogen or C₁₋₆alkyl, or R²³ is linked to R¹⁴ to form a ring of 4 to 10 atoms as hereinbefore described; where R²² is halo, C₁₋₄alkyl, (CH₂)₀₋₃C₃₋₈cycloalkyl, (CH₂)₀₋₃aryl, heteroaryl, Het or oxo, or R²² is linked to R¹⁴ to form a ring of 4 to 10 atoms as hereinbefore described; or a pharmaceutically acceptable salt thereof.
 2. A compound according to claim 1 in which Ar is selected from phenyl, pyridyl, pyridazinyl, pyrimidinyl, pyrazinyl, furanyl, pyrazolyl, imidazolyl and thienyl, which ring is optionally substituted by groups Q¹ and Q² as defined according to claim
 1. 3. A compound according to claim 2 in which Q¹ is fluorine, chlorine, methyl or methoxy and Q² is absent.
 4. A compound according to claim 1 in which A is cyclopentyl or cyclohexyl, optionally substituted by halogen, hydroxy, C₁₋₄alkyl or C₁₋₄alkoxy.
 5. A compound according to claim 4 in which A is unsubstituted.
 6. A compound according to claim 1 in which D is CR^(g) where R^(g) is hydrogen or C₁₋₄alkyl.
 7. A compound according to claim 1 in which W is —CH₂— or —CH₂CH₂—.
 8. A compound according to claim 1 in which X is C═O or —CH₂—.
 9. A compound according to claim 1 in which R¹ is hydrogen or methyl.
 10. A compound according to claim 1 in which B is —CH₂— or —SO₂—.
 11. A compound according to claim 1 in which M is selected from:


12. A compound according to claim 1 selected from: 16-cyclohexyl-3,6-dimethyl-17-phenyl-4,5,6,7,8,9-hexahydro-1H-13,15-(ethanediylidene)pyrrolo[2,1-f][1,2,7,10,13]thiatetraazacyclohexadecine-2,12(3H)-dione 10,10-dioxide, 17-cyclohexyl-3,6-dimethyl-18-phenyl-3,4,5,6,7,8,9,10-octahydro-14,16-(ethanediylidene)pyrrolo[2,1-f][1,2,7,10,13]thiatetraazacycloheptadecine-2,13-dione 11,11-dioxide, and pharmaceutically acceptable salts thereof.
 13. A compound according to claim 1 of formula (Ia):

or a pharmaceutically acceptable salt thereof, wherein W, X and M are as defined according to claim
 1. 14. A pharmaceutical composition comprising an effective amount of a compound of the formula (I), or a pharmaceutically acceptable salt thereof, according to claim 1 and a pharmaceutically acceptable carrier. 